Relief valve assembly

ABSTRACT

The present invention has completely broken from the unreasonable construction of conventional type of relief valve which places weight and lifting disc inside of upper body or lower body. In other words, lifting disc and weight are placed outside of upper body. It is brand-new construction that adopts casket-shaped housing forming flow slot which guides releasing gas to move upwards vertically when the above-mentioned lifting disc ascends by the releasing gas from tank. And also the present invention features that drain part is formed to drain all the time sea water or rain gathering inside of casket-shaped housing to outside of casket-shaped housing and brand-new construction of vacuum relief valve is equipped.

BACKGROUND OF THE INVENTION

1. Technical Field

The invention is related to relief valve assembly which can be equippedfor use at either vessels carrying oils or chemical products, or atchemical tank.

2. Description of the Prior Art

Conventional type of relief valve (ie: U.S. Pat. No.6,604,544/RE37,989/U.S. Pat. No. 5,060,688/U.S. Pat. No. 5,873,384), dueto it's constructional limitation that lifting disc and weight areplaced inside of upper body, causes low close pressure of valve,subsequently releases unnecessarily excessive amount of gas andconsequently leads to the problem with environmental pollution anddecrease in safety of tank and further uneconomical result.

And in case of relief valve used for vessel, a small amount of pressuregas which releases through the path between disc seat assembled withupper body and pressure disc does not release upwards to verticaldirection but to sideways to a wide spread owing to the influence ofwind by the characteristics of ocean circumstances and therefore can notguarantee the safety against fire and safety accidents.

Conventional type of relief valve, as it's lifting disc and standardweight are placed inside of upper body, does not allow proper release ofpressure gas, therefore makes it difficult to release the gas in shorttime, causes hammering phenomenon and is further quite inconvenient forcleaning and repairing when relief disc and weight are contaminatedowing to the volatile steam containing gas compound and high viscosityof solvent based foreign ingredients.

Moreover, while relief valve is kept sealed relief disc, weight and stemare always exposed to released gas so easy to erode and therefore callfor raw materials of high erosion resistance which are expensive thusuneconomical. Additionally, conventional type of relief valve, whenincreasing or decreasing the weight automatically requires disassemblingwhole upper & lower body out of tank and then working for replacement ofweight and therefore causes poor work efficiency and takes long periodof work time. All these troubles are not to be overlooked in reliefvalve assembly construction.

Reviewing these troubles further, as mentioned earlier the reason whyclose pressure of conventional type of relief valve is getting down inclose cycle is that lifting disc and weight are placed inside of upperbody so it is quite unavoidable to see disc and weight in the state offloating unnecessarily for a long time by the pressure of releasing gaswhile valve being closed. In other words, as disc and weight placedinside upper body are not provided with enough atmospheric pressure soclose pressure is naturally reduced and therefore valve opens for longtime more than necessary. And releasing gas passing through betweenpressure disc and disc seat assembled with upper body, withoutcasket-shaped housing(50) that can lead out gas upwards to verticaldirection, releases to sideways to a wide spread with top part of upperbody as a start point, so there arises more possibility of safetyaccident of workers and danger of fire.

As another inventional example, there is a relief valve that has beenclaimed to get rid of excessive release of pressure gas inside tank andpublicized as international reference No. WO 02/095275. The detailedconstruction of the main parts of this is intended to fix magnet inlower part of stem with which lifting disc and weight are assembled, andalso fix magnet inside of lower body and then have these upper/lowermagnets get closer or contact each other. Namely, these magnets are inthe state of dragging each other by magnetic force.

In such circumstances, pressure gas generated inside of tank, makesfarther the gap between the magnets in the state of above-mentionedmagnetic force and at the same time pushes upwards lifting disc andweight and then releases out to outside of upper body namely in the airbut in the meantime magnetic force between above magnets might still beworking even while pressure gas releasing out in the air. Therefore whenthe release pressure starts to decrease in accordance with reduction toreleasing amount of pressure gas after initial release of pressure gas,lifting disc and weight are forced to move down by magnet force andpressure disc closes valve. These technical considerations might beworthwhile to suggest.

However, in reviewing further above-mentioned international publicationNo. WO 02/095275, it has been noticed as a problem that this additionalconstruction is so complicated with lifting disc and weight fixed tostem, magnet of lower part of stem and magnet inside of lower body, andtherefore causes increase to manufacturing cost, makes it difficult tohandle due to heavy weight and also does not fit for the vessel thatneeds weight reduction. Therefore it's not easy for manufacturing,transporting, facilitating, and maintaining (repairing and replacingunits) so quite inconvenient in workability, and furthermore causesunreasonable trouble that in replacing magnet it is necessary toseparate from tank even lower body which is of heavy weight.

In addition to above, relief valve in above-mentioned internationalpublication No. WO 02/095275 also has the same problems and defects asafore-mentioned conventional type of relief valve because it's stem,lifting disc, weight, magnet in lower part of stem, magnet inside oflower body are all inside of upper body and lower body.

The followings are with regard to the problems and defects ofconventional type of vacuum relief valve.

Compared according to the FIG. 8 of the invention, conventional type ofvacuum relief valve which stably converts buoyant pressure generatedinside of tank to the level of atmospheric pressure as supersaturatedgas inside of tank releases out in the air is, composed of screencover(670) & screen hood(680) that are both in one unit or assembledwith body(600) and cast-iron, heavy weighed as a defect, so quiteimproper for vessels, complicated in fixing construction of screen(690),and therefore difficult to manufacture and inconvenient in assemblingand maintaining & repairing and further expensive.

Another example of vacuum relief valve contrived to make up for theseproblems and defects, compared according to the FIG. 8 of the invention,is intended to weld ring-shaped support unit to the center ofscreen(690) and make stem path through the above support unit, so theweight of the support unit is imposed on screen(690) and hence, as perthe elapse of time, screen(690) tends to droop down consequently leadingto the needs for frequent replacement or repairing work that is quiteinconvenient and uneconomical.

Along with this, conventional type of relief valve has the problem withdifficulty of proper gas releasing due to another flow variation ofreleasing gas which is caused by extra weight of assist weight whenadding assist weight to standard weight. Accordingly closure function ofdisk does not work consistently all the time when using standard weightonly and when using both standard weight and assist weight as well.

BRIEF SUMMARY OF THE INVENTION

In the relief valve which can be equipped for either vessels carryingoils or chemical products or for chemical tanks to safely releasepressure gas (supersaturated gas) inside of tank out in the air, theinvention is featured as structuring,

lower body(10) which is fixed through to tank and;

upper body(20) in which rib(22) is one-bodied with boss(23) having screwhole for assembling screw part(61) of stem(60) and with which discseat(21) is assembled and;

lifting disc(30) which has ring(33) at lower side, protruding stage(34)contacting with disc seat(21) of upper body(20) & closing valve, the 1sthole(32) penetrated by stem(60) and the 2nd hole(31) in whichstopper(62) assembled with stem(60) can move by cap nut(63) and;

weight(40) which is assembled with lifting disc(30) by bolt(80) and;

weight cover(70) which protects weight(40) and offers space inside toenable assembling assist weight(90) and;

fixable stem(60) which has screw part(61) assembled with boss(23) ofupper body(20) and guides lifting disc(30) to move up and down and;

stopper(62) which is fixed to top part of stem(60) by cap nut(63) andrestricts ascending distance of lifting disc(30) and;

casket-shaped housing(50) which is assembled with upper body(20) andleads releasing gas upwards out to vertical direction and;

water (sea water or rain) drain part(3) which is assembled by passingthrough flange(20-1) of upper body and flange(10-1) of lower body anddrains water (sea water or rain) gathering inside of casket-shapedhousing(50) to outside and;

vacuum relief valve(5) which is assembled with lower body(10) andfunctions to build up atmospheric pressure inside of tank.

And also in the relief valve which can be equipped for either vesselscarrying oils or chemical products or for chemical tanks to safelyrelease pressure gas (supersaturated gas) inside of tank out in the air,the invention is featured as structuring,

lower body(10 a) which is fixed through to tank and;

upper body(20 a) in which rib(22 a) is one-bodied with boss(23 a) havingscrew hole for assembling screw part(61 a) of stem(60 a) and with whichdisc seat(21 a) is assembled and;

lifting disc(30 a) which has protruding stage(34 a) contacting with discseat(21 a) of upper body(20 a) & closing valve, the 1st hole(32 a)penetrated by stem(60 a) and the 2nd hole(31 a) in which stopper(62 a)assembled with stem(60 a) can move by cap nut(63 a) and;

the 1st weight(40 a) which is assembled with lifting disc(30 a) bybolt(80 a) and has in the center bushing(150) assembled with the 2ndhole(31 a) of lifting disc(30 a) and;

the 2nd weight(40 b) which has ring(33 a) at lower side and assembledwith the 1st weight(40 a) by bolt(80 b) and;

weight cover(70 a) which is assembled with the 2nd weight(40 b) byweight cover bolt(110 a) and;

fixable stem(60 a) which has screw part(61 a) assembled with boss(23 a)of upper body(20 a) and guides lifting disc(30 a) to move up and downand;

stopper(62 a) which is fixed to top part of stem(60 a) by cap nut(63 a)and restricts ascending distance of lifting disc(30 a) and;

casket-shaped housing(50) which is assembled with upper body(20 a) andleads releasing gas upwards out to vertical direction and;

water (sea water or rain) drain part(3) which is assembled by passingthrough flange(20-1) of upper body and flange(10-1) of lower body anddrains water (sea water or rain) gathering inside of casket-shapedhousing(50) to outside and;

vacuum relief valve(5) which is assembled with lower body(10) andfunctions to build up atmospheric pressure inside of tank.

In the relief valve assembly, casket-shaped housing is featured as beingassembled with upper body(20) and flange(53) by bolts and nuts andbuilding up small diameter part(D1) which forms narrow slot(G) with sideof lifting disc(30), large diameter part(D2) which forms wide slot(G1)with side of lifting disc(30) when lifting disc(30) moves up and inclinepart(52) which is formed in the connection area between large diameterpart(D2) and small diameter part(D1).

In the relief valve assembly, another casket-shaped housing is featuredas being assembled with upper body(20 a) and flange(53 a) by bolts andnuts and building up small diameter part(D1) which forms narrow slot(G)with side of the 2nd weight(40 b), large diameter part(D2) which formswide slot(G1) with side of the 2nd weight(40 b) when the 2nd weight(40b) moves up and incline part(52) which is formed in the connection areabetween large diameter part(D2) and small diameter part(D1).

In the relief valve assembly, outside diameter of lifting disc(30) isfeatured as being larger than outside diameter of disc seat(21).

In the relief valve assembly, outside diameters of lifting disc(30 a) &the 1st weight(40 a) are featured as being larger than outside diameterof disc seat(21 a) and smaller than outside diameter of the 2ndweight(40 b).

In the relief valve assembly, water (sea water or rain) drain part(3) isfeatured as structuring,

vertical elbow(200) which forms screw(201) assembled through screwhole(20-2) in the flange(20-1) of upper body(20) screw hole(203) at theopposite side of screw(201) and;

horizontal elbow(300) which forms screw(303) assembled with screwhole(203) of vertical elbow(200),

gas releasing slot(302) upwards vertically and sea water or rain drainslot(301) downwards vertically.

In the relief valve assembly, another water (sea water or rain) drainpart(3) is featured as structuring,

inner part which is penetrated by hole(401), body(400) which is shaped“J”, head part(404) which is fixed through the holes(20-3)(10-3) ofupper body and lower body, tail part(405) which is at the opposite sideof head part(404) and faces upwards vertically, gas releasing slot(402)which is formed inside of tail part(405) and sea water or rain drainslot(403) which is formed at the bottom of body(400).

In the relief valve assembly, Vacuum relief valve(5) is featured asstructuring stem support(610) which is assembled through the hole(603)of lower part of body(600), the upper part of which is assembled withring seat(620) contacting with closure disc(630) and which has rib(611)& boss(612) and;

bushing(640) which is assembled with boss(612) of stem support(610) andsupports stem(660) assembled with closure disc(630) and;

screen cover(670) which is assembled with the lower part of stemsupport(610) and;

screen(690) which is assembled with screen cover(670) and screenhood(680) which is placed under screen(690) and has air hole(681) in thecenter and;

snap ring(650, 651) which is assembled with bushing(640) penetrating thecenter of screen(690) and prevents screen(690) from moving up and down.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a referential view indicating a state of operation of theinvention; and

FIG. 2 is a partially enlarged view of the relief valve according to the1st performance of the invention; and

FIG. 3 is a referential view indicating casket-shaped housing of theinvention; and

FIG. 4 is a partially enlarged view of the relief valve according to the2nd performance of the invention; and

FIG. 5 is a referential view indicating water (sea water or rain) drainpart of the invention; and

FIG. 6 is a cross sectional view of 500-500 in FIG. 5; and

FIG. 7 is a referential view indicating water (sea water or rain) drainpart representing another performance of FIG. 5; and

FIG. 8 is a cross sectional view of vacuum relief valve of theinvention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

The followings are to describe the composition and operating mechanismof the invention with reference to the drawings attached.

FIG. 1 refers to assembly drawing which indicates a state of operationin the 1st performance of the invention, and a state of closure ofrelief valve in which vacuum relief valve(5) is assembled with sides oflower body(10). And in FIG. 2 and FIG. 4 referring to relief valve,lever system which can manually operate lifting disc(30)(30 a) is notillustrated.

In relief valve of the present invention, as described earlier, liftingdisc(30)(30 a), weight(40), the 1st weight(40 a) and the 2nd weight(40b) are not placed inside of upper body(20)(20 a) or lower body(10)(10a). These are placed in the air upside of upper body(20)(20 a) asillustrated in the drawings. Casket-shaped housing(50)(50 a) is formedto guide releasing gas to flow upwards vertically. Water (sea water orrain) drain part(3) is newly formed and vacuum relief valve(5) of newconstruction is also formed. All the parts herein are featured as beingof new construction.

Also in relief valve of the present invention, it is so easy to replaceor repair the main parts inside of casket-shaped housing(50)(50 a)without separating upper body(20)(20 a) out of lower body(10)(10 a).Therefore relief valve of the invention is easy to manufacture andmaintain & repair. And with it's simple construction, it is lightweighed and so easy to handle and accordingly pretty suitable for reliefvalve of tank in land and vessel as well.

So to speak, relief valve of the invention represents a great deal ofconstructional difference from conventional type of relief valve (ie:U.S. Pat. No. 6,604,544/RE37,989/U.S. Pat. No. 5,060,688, U.S. Pat. No.5,873,384) and relief valve made by the technique from internationalpublication No. WO 02/095275 and therefore it can resolve the problemsand defects deriving from conventional type of relief valve.

Firstly, in the 1st performance lower body(10) is featured as havingvacancy inside without any parts assembled as shown in the drawing andbeing so easy to manufacture and light weighed. Especially it does notneed any parts obstructing release of gas and therefore enables itselfreleasing gas to pass through much properly.

Nextly, inside of upper body(20) which is assembled with lower body(10)by bolts and nuts, boss(23) is formed and united into one body withupper body(20) by rib(22). As there is hole in the boss(23), screwpart(61) of stem(60) can be simply assembled through screw hole ofboss(23). Therefore stem(60) of the invention, differently fromconventional type of relief valve, does not move up and down togetherwith weight, lifting disc and pressure valve at the same time but israther fixed to upper body(20) and shows no movement.

Disc seat(21) is assembled with upper body(20) and disc seat(21)contacts with protruding stage(34) of lifting disc(30). Lifting disc(30)forms the 1st hole(32) in the center area and lets stem(60) passthrough. Providing that stem(60) fixed to boss(23) is piston, liftingdisc(30) can be called as a cylinder moving up and down. So only liftingdisc(30) and weight(40) ascends together and releases gas out whilestem(60) is in fixed position. In further detailed review for theconstruction of lifting disc(30), the 2nd hole(31) and the 1st hole areformed and ring-shaped stopper(62) which is fixed by cap nut(63) isinside of the 2nd hole(31). Therefore ascending distance of liftingdisc(30) is restricted by stopper(62). In this case, stopper(62) can beassembled with the top of stem(60) by snap ring instead of cap nut(63).And as for the raw materials for stopper(60) it might be available toadopt metals, nonferrous metals, plastic or synthetic resins and so on.

And further, lifting disc(30) has ring(33) as shown in the drawing, andthis ring can be fixed by welding or united into one body with liftingdisc(30). The ring(33) make it easier for lifting disc(30) to ascend byreleasing gas passing through the gap between disc seat(21) andprotruding stage(34) of lifting disc(30). But in some case ring(33) canalso be out of adoption.

Nextly, lifting disc(30) is assembled with weight(40) by bolt(80). Whenthe weight of weight(40) needs to be added, it is simply required tokeep upper body(20) and lower body(10) as is, unfasten weight coverfixing bolt(110), separate weight cover(70) from weight(40), placeassist weight(90) on weight(40), and assemble again weight cover(70)with weight cover fixing bolt(110). But in case of conventional type ofrelief valve, it is required to separate upper body and lower body fromtank, replace weight or assemble assist weight and then assemble againupper body and lower body with tank. Therefore it causes poor workefficiency and inconveniences and costs much time. However the inventionis, needless to be compared with conventional type of relief valve, farconvenient, safe and makes it possible to finish the work in short timein adding weight.

Next part is with regard to casket-shaped housing(50) which is anothermain part of the invention. This is almost same as casket-shapedhousing(50 a) which will be described later according to the 2ndperformance.

Casket-shaped housing(50) represents the shape of casket which isrelatively thin. It forms large diameter part(D2) and small diameterpart(D1) and incline part(52) in the connection area between smalldiameter part(D1) and large diameter part(D2). This casket-shapedhousing(50) is assembled with upper body(20) and fixed with flange(53)by bolts and nuts. It is quite natural to manufacture inside diameter ofsmall diameter part(D1) of casket-shaped housing(50) larger than insidediameter of disc seat(21).

In the 1st performance of the invention, valve remains closed as shownin FIG. 1 and opened when pressure gas generated inside tank reaches astate of supersaturation. By this time pressure gas inside of tankcauses lifting disc(30) to ascend and separate valve seat(21) andprotruding stage(34). In this case lifting disc(30) can move up moreproperly with the help of ring(33). As illustrated above releasing gasascends vertically through the narrow slot(G) between small diameterpart(D1) of casket-shaped housing(50) and side surface of liftingdisc(30) and starts passing out in the air. Additionally as thereleasing amount of gas increases, lifting disk(30) is ascending more.As a result lifting disc(30) also comes to ascend and the amount ofreleasing gas increases. In other words ring(33) is placed at the higherposition than starting point(51) of incline part in casket-shapedhousing(50) and the amount of releasing gas increases. Therefore wideslot(G1) is formed between large diameter part(D2) of casket-shapedhousing(50) and side of lifting disc(30) and releasing gas ascendsvertically and passes out to a maximum extent.

One thing to be carefully reviewed here is that casket-shapedhousing(50) of the invention is exposed to the air and lifting disc(30)and weight(40) are also exposed to the air inside of casket-shapedhousing. In other words, differently from conventional type of reliefvalve, lifting disc(30) and weight(40) are not placed inside of upperbody(20). Accordingly it must not be overlooked as an important factthat atmospheric pressure is well maintained all the time in liftingdisc(30) and weight(40) of the invention.

Supersaturated gas swiftly releases in the air and the time collapsesthen the releasing pressure of gas is reduce. Accordingly liftingdisc(30) and weight(40) starts descending slowly. By this time liftingdisc(30) and weight(40) descends smoothly and swiftly to close valve onaccount of atmospheric pressure. So to speak lifting disc(30) andweight(40) are not placed inside of upper body(20) and therefore notinfluenced by the pressure of releasing gas at last stage and closedswiftly. The reason for this is that atmospheric pressure works wellalong with the weight of the parts together with the weight of liftingdisc(30) and weight(40). Therefore it is available to close valveswiftly without excessive release of gas.

The next refers to the 2nd performance of the invention. It shows littledifference in operation from the 1st performance but represents slightdifference to be reviewed in construction. In other words, upperbody(20) in the 1st performance & upper body(20 a) in the 2ndperformance and disc seat(21) in the 1st performance & disc seat(21 a)in the 2nd performance represent all the same constructions. And liftingdisc(30) in the 1st performance has almost same construction as liftingdisc(30 a) in the 2nd performance.

A slight difference noticeable is that stopper(62) in the 1stperformance is place inside of the 2nd hole(31) of lifting disc(30) butstopper(62 a) in the 2nd performance is placed inside of bushing(150) ofthe 1st weight(40 a). In addition to above-mentioned, the 1stperformance adopts one weight(40) but the 2nd performance adopts twoweights namely the 2nd weight(40 b) and the 1st weight(40 a). Of course,the weight of weight(40) in the 1st performance equals to the totalweight of two weights namely the 2nd weight(40 b) and the 1st weight(40a) in the 2nd performance.

Further slight difference in placement is that in the 1st performancering(33) is in lifting disc(30) but in the 2nd performance ring(33 a) isin the 2nd weight(40 b). The reason for this difference is that in the1st performance outside diameter of lifting disc(30) is larger thanoutside diameter of disc seat(21) so it is better to fix ring(33) inlifting disc(30) however in the 2nd performance outside diameters oflifting disc(30 a) and the 1st weight(40 a) are a little larger thanoutside diameter of disc seat(21 a) and outside diameter of the 2ndweight(40 b) is larger than outside diameter of disc seat(21 a). Andtherefore it is better to fix ring(33 a) in the 2nd weight(40 b).

And in the 2nd performance, it needs to be further noted thatbushing(150) assembled inside of the 1st weight(40 a) can be removedwhen necessary.

Further, casket-shaped housing(50 a) used in the 2nd performance isassembled with the top part of upper body(20 a) and flange(53 a) bybolts and nuts and has small diameter part(D1) forming narrow slot(G)with side of the 2nd weight(40 b) and large diameter part(D2) formingwide slot(G1) with side of the 2nd weight(40 b).

In conclusion, the function of casket-shaped housing(50 a) in the 2ndperformance is almost same as that of casket-shaped housing(50) in the1st performance and accordingly might be quite easy to understandwithout another explanation.

As illustrated, relief valve in the 1st & 2nd performances of theinvention does not open valve for longer time than necessary becauseclose pressure increases in close cycle. According to a test of theinvention it has been found that the ascending ratio of close pressurein close cycle increases by about 30˜40% against conventional type ofrelief valve.

As another reference, in the 1st performance packing(100) can beassembled in a lower face of weight(40). It can also be replaced withO-ring. Packing(100) might be safe in using because it prevents the gasinside of tank from leaking out of relief valve. However relief valve ismanufactured so precisely that it does not necessarily call forpacking(100).

As is the same case, packing(100 a) can also be removed in the 2ndperformance.I

Differently from conventional type of relief valve, lifting disc(30)(30a), weight(40), the 1st & 2nd weight(40 a)(40 b) of the invention arenot placed inside of upper body(20)(20 a). And these are little exposedto releasing gas in a state of closure of relief valve so do not causeerosion. Accordingly these do not have to use expensive raw material ofhigh erosion resistance and were therefore found very economical.Additionally in a test a good result has been noticed that casket-shapedhousing(50)(50 a) enables releasing gas to move upwards vertically andsafely pass out in the air and therefore almost eliminate thepossibility of danger of fire or safety accident.

Consequently out of overall review, it has come to the conclusion thatrelief valve in the 1st & 2nd performances of the invention never fallsin function behind relief valve made by the technique from internationalpublication No. WO 02/095275 mentioned earlier, is much cheaper inmanufacturing, simple in construction, light weighed, excellent inmaintenance and repairing and safety.

Next to be reviewed is water (sea water or rain) drain part(3) of theinvention.

Water (sea water or rain) drain part(3) of the invention can be adoptednot only for relief valve of the invention but also for conventionaltype of relief valve. Namely it must be provided that conventional typeof relief valve adopts casket-shaped housing(50)(50 a) same as orsimilar to the present invention.

As illustrated earlier, relief valve of the invention represents variousfeatures and merits against conventional type of relief valve. But onthe other hand, when sea water or rain gathers inside of casket-shapedhousing(50)(50 a) it gets concentrated and interrupts ascending &descending operation of lifting disc. Along with this it puts a badeffect on the proper releasing of gas. And it further makes parts suchas lifting disc, weight, upper body as well as casket-shapedhousing(50)(50 a) apt to be eroded.

According to this water (sea water or rain) drain part(3) of theinvention, as explained above-mentioned, has been contrived to resolveout the problems previously pointed out by draining all the time seawater or rain gathering inside of casket-shaped housing(50)(50 a)outwards properly.

The following is to review more details.

FIG. 5 refers to assembled drawing indicating operation state ofabove-mentioned drain part(3). It has itself so simple construction butplays an important role. That is to say, in the 1st performancescrew(201) of horizontal elbow(200) passes through the hole(10⁻²) whichis formed in the flange(10⁻¹) of lower body(10) and is assembled withscrew hole(20-2) which is formed in the flange(20-1) of upper body(20).

Accordingly, sea water or rain gathering inside of casket-shapedhousing(50) passes through the screw hole(20-2) in the flange(20-1) ofupper body(20) and enters inside of hole(202) of vertical elbow(200).And then screw(303) of horizontal elbow(300) is assembled through screwhole(203) of vertical elbow(200). In this case it is much better toassemble gas releasing slot(302) upwards vertically without fail.Additionally it is better to place drain slot(301) for sea water or rainat the opposite side of gas releasing slot(302) and downwards.

According to above-mentioned, once vertical elbow(200) and horizontalelbow(300) are assembled, sea water or rain entering inside of hole(202)of vertical elbow(200) runs through hole(304) of horizontal elbow(300)and passes out downwards through sea water or rain drain slot(301). Andlarge amount of sea water or rain more than the amount which can bereleased through sea water or rain drain slot(301) can also overflowthrough gas releasing path(302) downwards.

By the way, here comes needs to explain the reason for forming gasreleasing slot(302) in horizontal elbow(300).

As indicated in the drawing, in the flange(20-1) of upper body(20) thereis screw hole(20-2) in order to drain out sea water or rain gatheringinside of casket-shaped housing(50) and assemble vertical elbow(200).Therefore when supersaturated gas inside tank releases out in the airforcing up lifting disc(60), part of releasing gas enters screwhole(20-2) of upper body(20). Accordingly, part of releasing gasreleases out through screw hole(20-2), hole(202) of vertical elbow(200)and hole(304) of horizontal elbow(300). Therefore, horizontal elbow(300)necessarily requires forming gas releasing slot(302) upwards verticallyto ensure the safety of workers and reduce the danger of fire. In thiscase, the diameter of gas releasing slot(302) is larger than that of seawater or rain drain slot(301) and therefore the gas does not releasethrough drain slot(301) for sea water or rain. As for this reason, whenthe gas releases through releasing gas slot(302) buoyant pressure isimposed to sea water or rain drain slot(301).

Nextly to be reviewed is the 2nd performance as shown in FIG. 7. Thebody(400) of this is shaped “J” and has hole(401) all the way throughinside and accordingly lets supersaturated gas as well as sea water orrain pass through.

The 2nd performance inserts head part(404) inside of hole(10-2)(10-3) ofsame center point which penetrates flange(20-1)(10-1) of upper body andlower body and fix by welding.

In further review on FIG. 7, tail part(405) has gas releasing slot(402)connected with above-mentioned hole(401) and at a lower face ofbody(400) there is sea water or rain drain slot(403) connected withabove-mentioned hole(401).

This 2nd performance, as 1-piece type, has structural difference fromthe 1st performance which is 2-piece type but shows the same function.Therefore the detailed explanation on the function may be referred tothe 1st performance illustrated earlier.

Water (sea water or rain) drain slot(3) of the invention is assembledwith relief valve which has casket-shaped housing(50)(50 a). Thereforeit release all the time sea water or rain gathering inside ofcasket-shaped housing(50)(50 a) before concentrating and interruptingthe ascending & descending operation of lifting disc. And it also safelyreleases part of supersaturated gas flowing back downwards inside ofcasket-shaped housing upwards vertically only when supersaturated gasinside of tank releases through relief valve.

The next refers to vacuum relief valve(5) in FIG. 8.

In FIG. 8. vacuum relief valve(5) of the invention offers merit of muchsimple construction compared with outstanding conventional type ofvacuum relief valve. In other words, screen cover(670) and screenhood(680) are not cast-iron but made out of thin iron plate which ismanufactured by press process. Therefore the size of body(600) which iscast-iron has been reduced a great deal. Consequently the weight ofbody(600) shows distinctive reduction by around 10% to 30% compared withthat of body of conventional type of relief valve.

And further, fixing method of screen(690) is brand-new and simple aswell. And the problems with the weight imposed on screen(690) and theupwards & downwards movement of screen(690) have been resolved. Alongwith this screen cover(670) and screen hood(680) are made out of thiniron plate and accordingly very light weighed, inexpensive inmanufacturing cost. Therefore it is convenient for assembling withbody(600) and easy for maintenance & repairing. Of course a reduction inthe size of body(600) is featured as being easy for manufacturing,maintenance & repairing and reducing the cost.

In other words, vacuum relief valve of the invention, compared withconventional type of vacuum relief valve, gets lighter and smaller, hasreduced number of parts & offers simple construction. Therefore itoffers conveniencies in manufacturing and makes it easier to assemble,transport, maintain & repair. It also provides competitive price,especially even with a long term of operation screen(690) does not droopor move downwards and therefore durability of screen(690) greatlyincreases.

In reviewing more details, the invention has adopted the method thatscreen cover(670) and screen hood(680) made out of press process aremanufactured separately from body(600) and assembled with body(600) bybolts and nuts.

At the bottom area of body(600) there is hole(603) which allows the airoutside of tank to enter inside of tank. Stem support(610) is assembledwith this hole(603) as shown in the drawing. In this case, it is quitenatural to assemble stem support(610) with ring seat(620) which contactswith close disc(630). But in some case it is also available to eliminatering seat(620) and use stem support(610) instead. In other words, ringseat(620) can be united into one piece with stem support(610). Inaddition, boss(612) is formed in the center of rib(611) in stemsupport(610). Bushing(640) penetrates inside of above-mentionedboss(612). Bushing(640) has hooking tier(641) and hooking tier(641) ishooked with a upper face of boss(612) when assembled with boss(612) andcan therefore eliminates the problem with drooping downwards.

Nextly, a lower face of bushing(640) penetrates the center ofscreen(690). Therefore it is required to form in the center ofscreen(690) the hole which has a little larger diameter than outsidediameter of bushing(640). Further to this, round fan-shaped screencover(670) is placed at a lower face of afore-mentioned stemsupport(610). For this, screen cover(670) & stem support(610) are fixedat a lower face of body(600) by bolt(607).

Following the above-mentioned, one snap ring(650) is assembled with aupper face of bushing(640). And screen(690) is inserted to assemble withbushing(640) then another snap ring(651) is assembled with a lower faceof bushing(640). Therefore the position of screen(690) can be firmlyfixed on bushing(640) as shown in FIG. 8. As for this reason, upper &lower snap rings(650)(651) fix screen(690). As a next step, screenhood(680) is placed at a lower face of screen(690) and then screencover(670), screen(690) and screen hood(680) are fixed together bybolt(608) and nut(609).

What is then followed is to insert stem(660) to penetrate the center ofbushing(640) and also assemble stem(660) and close disc(630) byscrew(661) of stem(660). Of course it is common technique to assemblecover(605) on a upper face of body(600).

The invention with above-mentioned construction assembles screen(690)using bushing(640) with long length and two snap rings(650, 651) so doesnot impose any over weight on screen(690). By stably fixing screen(690)like this way screen(690) never droops downwards even with long term ofoperation. Along with this screen(690) does not move up and down so thedurability naturally improves a lot. And bushing(640) with long lengthplays a guiding role to lead stem(660) to properly move up and downwithout trembling sideways and therefore keeps screen(690) from beingexposed to excessive force and enables precise operation of closedisc(630).

The invention reviewed as above does not place lifting disc and weightinside of upper body or lower body but rather has these exposed in theair to make atmospheric pressure act properly. And by adopting simpleconstruction it makes it available to release out releasing gas swiftlyand smoothly. And by increasing close pressure in close cycle it makesit also available to keep valve from being opened for longer time thannecessary and prevents excessive release of gas. Therefore it offersbenefits of the safety of tank and economical advantages as well.

And more the invention, when using assist weight additionally, makes itavailable to keep assist weight covered safe inside weight cover. Andtherefore the invention, differently from conventional type of reliefvalve, does not allow any flow variation by releasing gas regardless ofnumber of weight used.

And also by adopting the construction of casket-shaped housing, theinvention allows releasing gas to move upwards vertically in the air andaccordingly makes it available to protect workers and keep away from thefire. Additionally the invention basically does not allow lifting discand weight to take a position inside of upper body or lower body.Therefore when valve is in a state of closure, lifting disc and stem arelittle eroded owing to gas or high viscosity of solvent based foreigningredients. Accordingly it makes it available to use normal type ofmetal instead of high-priced raw material and accordingly improveseconomical efficiency further.

Along with this, the invention makes it possible to simply disassembleand replace main parts without separating upper body from lower body andtherefore guarantees excellent properties in maintenance and repair andmore convenient cleaning work for parts.

And also, drain part(3) of the invention makes it available to drain allthe time sea water or rain gathering inside of casket-shaped housingbefore concentrating and interrupting ascending & descending of liftingdisc.

Vacuum relief valve of the invention is simple in construction, so easyto manufacture, maintain and light weighed therefore much suitable forrelief valve of storing tank including vessel for oil or chemicalproduct. And because of light weight & simplified construction it isconvenient not only in assembling but also in cleaning and thereforemuch economical. It can also fix screen stably by using bushing and snapring and therefore remove the problems with drooping and up & downmovement of screen. And also it enables stem to properly move up anddown without trembling and accordingly improves durability of screen agreat deal.

1. In the relief valve which can be equipped for either vessels carryingoils or chemical products or for chemical tanks to safely releasepressure gas (supersaturated gas) inside of tank out in the air, reliefvalve assembly featured as structure, lower body (10) which is fixedthrough the tank and; upper body (20) in which rib (22) is one-bodiedwith boss (23) having screw hole for assembling screw part (61) of stem(60) and with which disc seat (21) is assembled and; lifting disc (30)which has ring (33) at lower side, protruding stage (34) contacting withdisc seat (21) of upper body (20) and closing valve, the first hole (32)penetrated by stem (60) and the second hold (31) in which stopper (62)assembled with stem (60 an move by cap nut (63) and; weight (40) whichis assembled with lifting disc (30) by bolt (80) and; weight cover (70)which protects weight (40) and offers space inside to enable assemblingassist weight (90) and; fixable stem (60) which has screw part (61)assembled with boss (23) of upper body (20) and guides lifting disc (30)to move up and down and; stopper (62) which is fixed to top part of stem(60) by cap nut (63) and restricts ascending distance of lifting disc(30) and; casket-shaped housing (50) which is assembled with upper body(20) and leads releasing gas upwards out to vertical direction and;water (sea water or rain) drain part (3) which is assembled by passingthrough flange (20-1) of upper body and flange (10-1) of lower body anddrains water (sea water or rain) gathering inside of casket-shapedhousing (50) to outside and; vacuum relief valve (5) which is assembledwith lower body (10) and functions to build up atmospheric pressureinside of tank.
 2. In the relief valve which can be equipped for eithervessels carrying oils or chemical products or for chemical tanks tosafely release pressure gas (supersaturated gas) inside of tank out inthe air, relief valve assembly featured as structuring, lower body (10a) which is fixed through to tank and; upper body (20 a) in which rib(22 a) is one-bodied with boss (23 a) having screw hole for assemblingscrew part (61 a) of stem (60 a) and with which disc seat (21 a) isassembled and; lifting disc (30 a) which has protruding stage (34 a)contacting with disc seat (21 a) of upper body (20 a) & and closingvalve, the 1^(st) first hole (32 a) penetrated by stem (60 a) and thesecond hole (31 a) in which stopper (62 a) assembled with stem (60 a)can move by cap nut (63) and; the first weight (40 a) which is assembledwith lifting disc (30 a) by bolt (80 a) and has in the center bushing(150) assembled with the second hole (31 a) of lifting disc (30 a) and;the second weight (40 b) which has ring (33 a) at lower side andassembled with the f+first weight (40 a) by bolt 80 b) and; weight cover(70 a) which is assembled with the second weight (40 b) by weight coverbolt (110 a) and; fixable stem (60 a) which has screw part (61 a)assembled with boss (23 a) of upper body (20 a) and guides lifting disc(30 a) to move up and down and; stopper (62 a) which is fixed to toppart of stem (60 a) by cap nut (63 a) and restricts ascending distanceof lifting disc (30 a) and; casket-shaped housing (50) which isassembled with upper body (20 a) and leads releasing gas upward out tovertical direction and; water (sea water or rain) drain part (3) whichis assembled by passing through flange (20-1) of upper body and flange(10-01) of lower body and drains water (sea water or rain) gatheringinside of casket-shaped housing 50 to outside and; vacuum relief valve(5) which is assembled with lower body (10) and function to build upatmospheric pressure inside of tank.
 3. As claimed in the claim 1,relief valve featured as having casket-shaped housing assembled withupper body (20) and flange (53) by bolts and nuts and building up smalldiameter part (D1) which forms narrow slot (G) with side of lifting disc(30), large diameter part (D2) which forms wide slot (G1) with side oflifting disc (30) when lifting disc (30) moves up and incline part (52)which is formed in the connection area between large diameter part (d2)and small diameter part (D1).
 4. As claimed in the claim 2, relief valvefeatured as having casket-shaped housing assembled with upper body (20a) and flange (53 a) by bolts and nuts and building up small diameterpart (D1) which forms narrow slot (G) with side of the second weight (40b), large diameter part (D2) which forms wide slot (G1) with side of thesecond weight (40 b) when the second weight (40 b) moves up and inclinepart (52) which is formed in the connection area between large diameterpart (D2) and small diameter part (D1).
 5. As claimed in the claim 1,relief valve featuring that outside diameter of lifting disc (30) islarger than that of disc seat (21) diameter of disc seat (21).
 6. Asclaimed in the claim 2, relief valve featuring that outside diameters oflifting disc (30 a) and the first weight (40 a) are larger than outsidediameter of disc seat (21 a) and smaller than outside diameter of thesecond weight (40 b).
 7. As claimed in the claim 1, relief valveassembly featuring water (sea water or rain) drain part (3) which has,vertical elbow (200) forming screw (201) assembled through screw hole(20-2) in the flange (20-1) of upper body (20) and screw hole (203) atthe opposite side of screw (201) and; horizontal elbow (300) formingscrew (303) assembled with screw hole (203) of vertical elbow (200) andgas releasing slot (302) upwards vertically and sea water or rain drainslot (301) downwards vertically.
 8. As claimed in the claim 1, reliefvalve assembly featuring water (sea water or rain) drain part (3) whichhas, inner part penetrated by hole (401), body (400) shaped “J”, headpart (404) fixed through the holes (20-3) (10-3) of upper body and lowerbody, tail part (405) facing upwards vertically at the opposite side ofhead part (404), gas releasing slot (402) formed inside of tail part(405) and sea water or rain drain slot (403) formed at the bottom ofbody (400).
 9. As claimed in the claim 1, relief valve assemblyfeaturing vacuum relief valve (5) which has, stem support (610) which isassembled through the hole (603) of lower part of body (600), the upperpart of which is assembled with ring seat (620) contacting with closuredisc (630) and which has rib (611) and boss (612) and; bushing (640)which is assembled with boss (612) of stem support (610) and supportsstem (660) assembled with closure disc (630) and; screen (690) which isassembled with screen cover (670) and screen hood (680) which is placedunder screen (690) and has air hole (681) in the center and; snap ring(650, 651) which is assembled with bushing (640) penetrating the centerof screen (690) and prevents screen (690) from moving up and down.